Internal mold release agents used in the production of molded polyurethane and polyurea products are known. U.S. Pat. Nos. 4,201,847 and 4,254,228 describe an internal mold release which is the reaction product of an organic polyisocyanate and an active hydrogen containing fatty acid ester. U.S. Pat. No. 4,111,861 describes four different classes of internal mold releases: i) mixtures of aliphatic or aryl carboxylic acid and a polar metal compound; ii) carboxyalkylsiloxanes; iii) aliphatic glyoximes; and, iv) aralkyl quaternary ammonium salts. Other known release agents include salts of acids (such as oleic acid) and primary amines (see, U.S. Pat. No. 3,726,952), reaction products of long chain fatty acids and ricinoleic acid (see, U.S. Pat. No. 4,058,492), and salts of acids (such as oleic acid) and tertiary amines (see, U.S. Pat. No. 4,098,731).
Zinc carboxylates containing from 8 to 24 carbon atoms per carboxylate group have also been described (U.S. Pat. Nos. 4,519,965, 4,581,386, 4,585,803 and 4,764,537, and British Patent 2,101,140). Release agents containing zinc carboxylates in combination with primary or secondary amine compatibilizers and an organic material containing a carboxylic acid group, a phosphorous containing acid group or a boron containing acid group, are described in published European Patent Application 0,119,471.
Most recently, a system which provides release from a bare metal mold has been developed. The system utilizes the reaction product of an organic polyisocyanate and an active hydrogen containing fatty acid ester in the A-side and a zinc carboxylate in the B-side (see, U.S. application Ser. No. 260,650, now U.S. Pat. No. 4,868,224 filed Oct. 21, 1988). One problem with this system is that the zinc carboxylate/solubilizer combination catalyzes the hydroxyl/isocyanate reaction. This makes the system relatively fast, leading to difficulties in filling large molds.
It is known to add fatty acids to polyurea systems in order to increase the green strength and aid in mold release (see, U.S. Pat. No. 4,499,254).